Saw 3D

serve himself, and that’s because he’s not a Jigsaw survivor at all. He’s a pants-afire liar, so Hoffman (Costas Mandylor), the killer since the real Jigsaw (Tobin Bell) died many movies ago, kidnaps Bobby and forces him to navigate through an underground maze where each room poses a deadly threat to Bobby’s PR army. Bobby has an hour to wind his way through it or his wife (Gina Holden, TV’s “Harper’s Island”) will become a victim as well.

Meanwhile, Hoffman still has time to hunt down Jigsaw’s widow, Jill (Betsy Russell), who’s turned him in to the cops, as well as set up ridiculously elaborate traps for various ne’er-do-wells “ from cheaters to racists “ who serve no further purpose to the film once snuffed.

Where does Hoffman find these people and how does he know about them? Isn’t his real estate agent the least bit suspicious about his penchant for rundown properties? Does he take advantage of Home Depot’s 12-month/no-interest card in purchasing his equipment? And what does he get with his Best Buy Reward Zone points for all the TVs he buys? More TVs?

Does it matter? This series is not about filling endless plot holes, but expending its mental energy on coming up with new ways to dispatch its amateur-hour cast members, and “Saw 3D” throws out a couple of doozy set pieces to make even the most immune gorehound flinch.